Means for braking engine-driven vehicles



March 8, G. HOXTON MEANS FOR BRAKING ENGINE DRIVEN VEHICLES Filed June20, 1923 2 Sheets-Sheet 1 March 8, 1927- HQXTON MEANS FOR BRAKING ENGINEDRIVEN VEHICLES Filed June 20, 1923 2 Sheets-Sheet 2 Patented Mar. 8,1927.

UNITED I STATES LLEWELLYN G. HOXTON, UNIVERSITY, VIRGINIA.

MEANS FOR BRAKING" ENGlINE-DRIVEN VEHICLES.

Application filed J'une 20, 1923. Serial No. 646,723.

Mv invention relates to the retardation or stopping of motor vehicles,such for example, as those driven by gas or steam engines, and broadlystated my object is to accomplish this efficiently by causing theso-called kinetic energy of the vehicle, that is the energy of themoving vehicle, as in descending a hill or its momentum in moving on alevel to be expended in compressing an aeriform fluid. The energy thusstored may either be purposely dissipated or utilized in various ways.Some of these are noted hereinafter. It is a common practice in motorvehicles to move the engine pistons by the power of the moving vehicle,to check or retard the movement of the vehicle, but this practice is noteflioient because the pressure produced in the cylinder on thecompression stroke of the pistons is applied to the pistons on thereturn stroke, and thus the pur- Dose of the operation is defeated inlarge part. By my invention, as will be made plain from what follows,the Work that is done by the pistons on the compression stroke is notexpended on or given back to the pistons, but is dissipated or disposedof so-as to avoid any suchaction.

As will be apparent, my invention may be embodied in many forms, and ofcourse, efficiency will vary with the forms of mechanism utilized. Ishow in the drawings a variety of embodiments of my invention, and allwill be found characterized by the fact that the motion of the engine orother piston in one direction is against the gas or aeriform contents ofthe cylinder and that the pressure thus produced or built up isprevented from acting on the piston in a reverse stroke thereof.

In the drawings:

Fig. 1 is a view in longitudinal section, of enough of the mechanism toillustrate a form of my invention applied to a gas engine to which airis admitted to the cylinders through a valve controlled port in themanifold beyond the carbureter and the release or discharge of thepressure produced is veffected through .the exhaust;

Fig.2 is a side elevation of enough of the mechanism to illustrate anembodiment of my invention in which the desired effect is obtained bymanipulation of the inlet and exhaust valves of the gas engine; Fig. 3is a section on the line 3-3 0 Fig. 2;

Fig. 4.- is a top plan view of several of the cylinders of the gasengine illustrating a form of my invention in which manually controlledvalves are provided on the cylinder heads; 7

Fig. 5 is a section on the line 55 of Fig. 4;

Fig. 6 is a vertical section of a form of my invention in which anautomatic blowofl valve is provided on the cylinder head; 6

-Fig. 7 is a side elevation of. a form of my invention in which thepressure produced by the pistons in securing the braking or retardingeffect is stored in a receiver for utilization Fig. 8 is a view inlongitudinal section of a form of my invention in which the usual enginethrottle is employed to permit the compressible fluid against which thepistons are to work to enter the cylinders, such fluid 1n the case ofthe gas engine being the gas and air mixture the ignition of the gas in,the cylinders being prevented as by opening the ignition circuit.

Fig. 9 1s a view illustrating another em- 99 bodiment of my invention.

It will, of course be understood that at the time the retarding orbraking is to be done the engine is kept in gear with the driving wheelsof the vehicle so that from the motion of the vehicle the pistons in thecylinders will be reciprocated through the usual driving connectionsbeing driving wheels and engme shaft, but I have not considered itnecessary to illustrate in full or in all the figures of the drawingsthe driving connection between the drlving wheels and the en e.

fie ferring to the embodiment of my invention shown in Fig. l themanifold, 10, at a 05 point beyond the carbureter has a port, 11, with avalve seat for a disk valve, 12, having a stem, 13, in guides inacasing. 14, bolted to the outside of the manifold and which by a portor opening, 15, is in communication 1 with the outside air so that whenthe valve,

12, is ofl" its seat and in response to the suction of the pistons airwill be drawn throu h the opening, 15, and the casing 14, into t emanifold and thence into the cylinders through the'inlet valves of theengine. A bell crank lever, 16, has one arm passed through the opening,15, to engage a collar, 17, on the valve stem so as to move the valve bythe rocking of the lever, and the other arm of the bell crank lever isconnected by a rod, 18, with a crank arm, 19, on a rock shaft, 20, whichby a pedal, 21, in convenient reach of a car driver may be rocked in thedirection to move the valve, 12, off its seat.

It will be observed that the construction and arrangement of the valvemechanism for the air intake preserves the original stream-line designof the manifold, the

valve, 12, being a thin disk which lies parallel with the axis of themanifold and when seated does not project into the manifold.

In the exhaust pipe, 22, is a valve seat, 23, formed or provided in ahollow casting, 24, which is inserted in the exhaust pipe, the valveseat, 23, being at right angles to the longitudinal axis of the exhaustpipe and a valve, 25, is movable to and from the seat, 23, the valve 25,being attached to a pivot, 26, so that the valve may swing betweenvertical, seat-engaging position and a horizontal position (as shown indotted lines) parallel with and to one side of the exhaust pipe, 22, soas not to interfere with easy exit of exhaust gases. The closing andholding of the valve, 25, to its seat is also eflected from the pedalshaft, 20, which has a crank arm, 27, that is connected by a link, 28,with a crank arm, 29. on a rock shaft, 30, which passes transverselythrough the casting, 24, and within the latter has attached an arm orlever, 31, that has a valve-engaging free end of such form that itswings the valve, 25, tight against its seat and locks rit there againstthe engine pressure upon the valve, the locking effect being produced byhaving the lever when in looking position lie in a straight line ornearly so from the valve to the pivot, 30. A spring, 32, attachedconveniently to the lever, 29, at one end serves to lift the valveseating and looking lever. 31, to valve-releasing position and to rockthe pedal shaft, 20, in the direction to lift the pedal and to causeseating of the air inlet valve, 12. A spring, 260, applied to the shaft,26, acts to rock the valve, 25, to open position when the lever, 31,releases the valve, 25, the opening of the valve being helped byaccumulated pressure thereon in the exhaust pipe. To diminish frictionof the lever, 31, in pressing against the valve a roller or ball, 310,may be provided where they come in contact. The casing casting, 24, mayhave provision for a muffler cut-out 240, when the casting with thevalve mechanism therein is located in advance of the mufller.

Of course, I do not restrict myself to such a valve as, 25, for otherforms may be used. In the form of my invention shown in Fig. 1 it willbe seen that so long as the valve, 12, is 0 en and the valve, 25, isclosed air will rawn into the engine cylinders passing by the inletvalves of the engine and forced into the exhaust pipe and retained andcompressed therein. The valves, 12, and 25, are so timed that the valve,12, begins to open and its opening is well advanced, before the valve,25, becomes seated so that there will be no danger from accidental fireof an explosive mixture confined in the exhaust line, since ample timeis allowed for the exhaust line to be flushed out of all exhaust gases.

If desired, to increase the volumetric capacity of the device shown inFig. 1 an air receiver may be connected with the exhaust pipe. Suchreceiver may as shown be in one with the muffler, that is to sayreceiver and muffler, 22 may be one and situated in the exhaust pipe,22, in advance of the valve, 25. Of course, the receiver may be separatefrom-the mufller. The receiver by increasing volumetric capacityincreases the effectiveness of the devicefor when air from the highpressure exhaust is admitted to the cylinders at atmospheric pressurethe total resulting pressure drop will be minimized. If desired anautomatic safety valve, 22 may be applied to the exhaust pipe and amanually controlled relief valve 22 may be provided having connectionswith an operating device conveniently accessible at the drivers seat.

The efficiency of the construction shown in Fig. 1 wherein the engine ismade to operate as an air compressor may be increased by the provisionof means for manipulating the intake and exhaust valves of the engine,it being possible to double the rate of pumping per crank shaftrevolution by appropriate manipulation of such valves. For suchmanipulation of the 1ntake and exhaust valves the arrangement shown inFig. 1 may be employed which provides a space between the stems of theintake and exhaust valves and theirrespective pusher or lifting rods andproviding a block, 33, in each case that is shiftable into and out ofsuch space and so shaped that when it is out of the space it Will engagethe valve stem and also anauxil ary pusher, 34, which is operated by anauxiliary cam, 35, on the cam shaft, 36. By this engagement on the downstroke of the engine pistons only the intake valves open and upon upstroke only the exhaust valves open. The blocks, 33; are pivotallymounted upon a longitudinal movable shaft, 37 which is connected withthe pedal, 21, so that simultaneously with the operation of the valve,12, said blocks will be shifted to change the vnormal timing of theengine valves when the valve, 12, is open and restore such normal timingwhen the valve, 12, is closed.

In the embodiment of my invention shown in Figs. 2 and 3 the brakingeffect is produced by mere manipulation of the intake and exhaust valvesof the engine, the intake valves being kept in a closed position and theexhaust valves being opened and closed so as to permit the successiveintake of air there-through into the cylinders, its compression therein,and its passage therefrom through the exhaust pipe so that there is aseries of compressions and releases in the engine cylinders. This actionmay be accomplished as shown in Figs. 2 and 3 by providing a spacebetween the stems of the intake and exhaust valves and their respectivecam-operated pusher or lifting rods and providing a shiftable block ineach case capable of filling such space that may be moved into and outof the space so that only when such block is in the space the aliningstems and pusher rods will be effective to lift the valves from theirseat; and providing in the case of the exhaust valves a supplemental orauxiliary cam on the cam shaft and an auxiliary pusher rod which by theaction of the auxiliary cam will move the exhaust valve off its seat.The block, 330, for the inlet-valve is on the extremity of a radial arm,331, on a sleeve. 332, mounted to rock on a longitudinally shiftableshaft or rod, 370, mounted parallel with the engine cam shaft, 360, theblockbeing thus shiftableinto and out of the space between the inletvalve stem, 38, and its cam-actuated lifting rod, 39, and similarly theblock, 40, for the exhaust valve is on the extremity. of a radial arm,'41, onea sleeve, 42, on the shaft, 370, but the block, 40, has alongitudinal extension, 43, which when the block, 40, is withdrawn fromthe space between lifting rod and valve stem is in position to engagethe valve stem, 44, (but which is never touched by the exhaust valvelifter rod 45) so that when an opposite extension, 46, of said block isin position to be engaged by the auxiliary valve lifter rod, 47, throughthe action of an auxiliary cam, 48, the exhaust valve will be liftedfrom its seat. l-Vhen the blocks, 330, and 40, are inserted in the spacebetween their respective valve stems and pusher rods the blockextension, 46, is out of alineinent with the auxiliary pusher rod, 47,and heme the engine valves act normally. The ends of the blocks andtheir extensions towards the stems are sloped or inclined so as readilyto pass the stems and there .is a slight projection between the aliningstems even when the blocks are withdrawn from the spaces between them toprevent the swinging of the arms carrying the blocks out of position toprevent their ontrance into the spaces between the pushers and stems.The auxiliary cam, 48, has two projections, 49, equi-distant apart sothat the auxiliary pusher rod, 47 is lifted twice for each revolution ofthe cam shaft-,- and the timing is such that the exhaust valve will openat the beginning. of the down stroke of the piston and close at the endof such stroke.

In the form of my invention shown in Figs. 4 and 5 provision is made fortaking air directly into the cylinder from the atmosphere by means of avalve ap' lied to the head of such cylinder and w ioh is manually openedand closed by the driver. In the case of engines already in use the aircommunication between the interior and exterior of the cylinder may behad through a priming spark plug, 50, applied to the head, 51, of eachcylinder and connecting each valve, 52, to a counter shaft, 53, by meansof a link, 54, and a crank, 55, on the counter shaft, 53, the counter.shaft having its rear end in convenient positionv to be reached by thedriver on his seat and having a suitable turning head or crank forrocking the counter shaft to open and close the priming spark plugvalves, 52. In design ing an engine with special reference to the use ofsuch a device a special valve could be applied to the engine headinstead of using the priming spark plug. It will be seen that when boththe intake and exhaust valves are closed during the normal com pressionand working strokes of the piston compression of air in the cylinderwill result in a braking eflect which may be determined by the degreeofclosing of the valve, 52. On the working stroke (hav'n reference to theengine working normally? air' will leak into the c linder and on thenormal compression stro e air will leak out, but during normal suctionand exhaust strokes there is no braking action since the intake exhaustvalves respectively will then be open.

As shown in Fig. 6 of the drawings each cylinder may be provided with avaflve applied to the cylinder head which will 0 en to allow the taking0% of pressure wit in the cylinder when a certain degree of pressure isproduced therein upon air admitted to the cylinder through a valvedevice such as is shown in Fig. 1 or upon fuel drawn through thecarbureter but with the ignition circuit broken so that the fuel willnot be exploded. The valve shown in Fig. 6 may be applied to a primingspark plug and comprises a conical seat, 56, in the passage into thespark lug and a conical valve, 57, vertically slida le in a tube, 58, inwhich the valve stem is guided and which contains a coil spring, 59,around the valve stem that yieldingly holds the valve to its seat andwhose tension may be adjusted by a nut or a head, 60, screwed into the uper end of the tube, 58. The upper end 0 the valve stem is adapted to beengaged by an eccentric 61, ona counter shaft, 62, that has one end inposition for bein convenientl reached by the driver so t at when the saft, 62, is in one position the eccentric,

thus no interference with the normal action 7 of the engine can takeplace. When the valve, 57, lifts from its seat the air or gas dischargeto the external air is through several down-turned passages, 63, whichlead from the valve seat, 56, this direction of the passages and theshape of the adjacent surfaces of the valve, 57, being employed toretard the seating of the valve, 57, for a while beyond the timerequired for the pressure within the cylinder to drop to the pressurewhich caused the opening of the valve so that by the time the valvecloses the pressure within the cylinder is much lower than the blow-offpressure.

In the various forms of my invention thus far described no provision ismade for utilizing the work done by the engine in compressing the air orgas contents of the cylinder, but I contemplate a receiver or reservoirfor the compressed medium so that the energy stored may be utilized. InFig.7 I show an arrangement by which the braking or retarding effect issecured by means of an air compressor or pump, 641, which has an outlet,65, that leads to a tank or receiver, 66, having an outlet, 67, whichmay be connected with the tire valves of a car to inflate the same andwhich .has asafety valve, 68, and a manually controlled outlet valve,69. The pump shaft has a slidable pinion, 70, splined to-it so that by alever, 71, accessible from the drivers seat, the pump may be connectedwith or disconnected from the s ur gear, 72, on the engine fly wheel,73. ome of the energy delivered to the compressor pump is dissipatedpartly in heat, the pump having radiating fins, and partly by throttlingaction by manipulation of the valve, 69. When the arrangement shown inFig. 7 is employed it is desirable to provide means for stoppingcarburetion, to avoid waste of gas either by combustion thereof or itsloss without being burnt. To prevent carburetion a valve mechanism 140,such as that shown in Fig. 1 may be provided .in the intake manifoldbeyond the carbureter having a bell'crank lever, 160, which is connectedby a rod, 180, with the lever, 71, so that when the pinion, 70, isthrown into mesh with the gear, 72, the bell crank, 160, will open thevalve mechanism, 140, to allow the influx of air into the manifold. Thereceiver, 66, will serve to smooth out any pulsating action in theretarding effort arising from the operation of the pump.

The-pump, 64, may have a construction by which it will act as amotor orengine, being provided for that purpose with well known valve gears, asthe Stevenson'or VValschaert or any valve gears that will reverse thedirection of rotation of the shaft of a reciprocating steam engine, sothat compressed air stored in the receiver may be utilized to operatethe pump as an engine or motor for starting purposes, the pin1on 70, andgear, 72, being placed in mesh for that purpose.

' If desired instead of the pump geared to the fly wheel, a receiversuch as the tank, 66, could be connected with the exhaust pipe in theconstruction shown in Fig. 1 so that the air taken into the engine andcompressed would be deli ered into such receiver instead of beingdischarged into the air, I show in Fig. 9 such an arrangement, theexhaust pipe, 220 being connected by a check valve, 74, with a receiver,660, having an automatic safety valve, 680, a manually operable outletvalve, 690, and an outlet pipe, 670.

I have mentioned before the use of gas and air mixture from thecarbureter in the engine cylinder to secure the braking or retardingaction. I illustrate in Fig. 8 a construction for that purpose, in whichthe usual carbureter throttle, 75, may be moved to wide open positionand at the same time the ignition circuit broken by means of a rockshaft, 76, with a pedal or other means for rocking it convenient to thedriver to which is fixed a crank, 77, that has a contact, 78, foropening and closing the ignition circuit, 79, and which by a rod, 80, isconnected With a crank arm, 81, which by a link, 82, is connected to therear side of the throttle valve, and thus avoids any pivot holes fortheslever, 81, through which leakage might occur.. The rod, 80, has aspring section, 83, of well known construction which permits thethrottle to be opened or closed or operated as usual regardless of. thepresence of the braking device.

What I claim is:

1. The combination of the manifold of an internal combustion enginehaving beyond the carburetor a .passage for air received from a pointoutside the manifold, a valve for opening and closing such passage, anexhaust pipe for the engine, a valve for opening and closing suchpipe,and means for simultaneously opening one valve and closing the other. I

2. The combination of the manifold and the exhaust pipe of an internalcombustion engine, a valve for controlling communication between themanifold and the external air, a valve casing applied to the exhaustpipe having a valve seat that extends transversel of the pipe, and avalve mounted in suc casing to move from a position crosswise of thepipe in contact with the seatto a position at one side thereof.

3. The combination of the manifold and the exhaust pipe of an internalcombustion engine, a valve for controlling communication between themanifold andthe external air, a valve casing applied to the exhaust pipehavin a valve seat that extends transversely of t e pipe, a valvemounted in such casing to move from a position crosswise of the pipe incontact with the seat to a position at one side thereof, and a valveengaging lever mounted in said casing for engagement with the side ofthe valve opposite the seat.

4. Means for retarding the motion of engine driven vehicles comprisingmeans for building up pressure from onward move- 10 ment of the vehicleindependently of its onward movement by the engine and that preventsapplication of the energy thus stored up to the engine, comprising meansfor admitting an aeriform fluid to the engine and its dischargetherefrom, and means for the concurrent control of the operation of theinlet and exhaust valves.

In testimony whereof I hereunto affix my signature.

LLEWELLYN G. HOXTON.

